Statue of Saint Gildas near the village of Saint-Gildas-de-Rhuys (France).
We know that the Roman legions invaded Britannia around the year 43. The early story of the arrival of the first Christians has been preserved by St. Gildas in his work De Excidio Britanniae (The Destruction of Britain). He wrote it only in the sixth century, but it is reasonable to think that Christians, military or civilians, came with the Roman legions. In addition, before this phase of the conquest, the Roman Empire was already present in Britannia.
Gildas (Breton: Gweltaz, c. 500–570)— also known as Gildas the Wise or Gildas Sapiens — was a 6th-century British monk best known for his scathing religious polemic De Excidio et Conquestu Britanniae, which recounts the history of the Britons before and during the coming of the Saxons. He is one of the best-documented figures of the Christian church in the British Isles during the sub-Roman period, and was renowned for his Biblical knowledge and literary style. In his later life, he emigrated to Brittany where he founded a monastery known as St. Gildas de Rhuys.